I'm with Pookie and GMC.
I've owned both. As time goes on, I'm getting a bit more frugal and common sense. I sold the 35 f/1.4L a long time ago after I got the 24-70 f/2.8L II. If you get a good copy of the 24-70, it will replace most of your other lenses for most needs. OTOH, if you have a specific subject or need that only a high end prime will satisfy, by all means, get the prime!
If you're not sure, RENT IT FIRST! Don't sell, buy or commit until you're sure after using it.
Keep in mind also that as camera bodies get better and better, esp with respect to High ISO, the need for a expensive general purpose f/2.8 zoom decreases unless it's the finer DOF isolation that you are after. And if that's the case, the extra fast prime may be the better way to go if you're not primarily compensating for low light. See? Two different situations, two different lenses.
If you are seeking a less expensive but highest L quality kit that will provide the most flexibility... Get a 5D3, 24-70 f/2.8 II and a 70-200 f/2.8 II and call it a day. Add a specialty EF lens or two to the mix for fun and you're good to go. Something like the 40 pancake, 35 f/2 or 50 f/1.4. Or even the 85 f/1.8. I love my EF 15mm f/2.8 FishEye too!
In fact, as good as L lenses are, you will be hard pressed to tell a practical difference in the quality of most EF lenses when compared to L. Sure it's there but will anyone else see it? Part of the reason I own mostly L lenses is due to my outdoor use and the fact that L lenses hold their value very well so when I want to sell one, I will probably get 70-90% of my investment back. (Esp if I buy it used to start with.) Heck, I've even made profit on a couple of lenses I bought used and sold after a couple years.
Of course, if you're just in it for the fun like me, maybe buying L lenses is just what you want to do. I get it. I love L lenses but I'm not kidding myself. I could make do with mostly EF lenses. I'm not a big time pro. I'm just an addicted enthusiast that shoots tens of thousands of images a year for free and most pros probably love to hate. LOL! 8)